The optimal threshold for initiating HIV treatment is unclear.
To compare different thresholds for initiating HIV treatment.
We used our validated computer simulation to weigh important harms from earlier initiation of antiretroviral therapy (toxicity, side effects, and resistance accumulation) against important benefits (decreased HIV-related mortality).
Veterans Aging Cohort Study (5742 HIV-infected patients and 11 484 matched uninfected controls) and published reports.
Individuals with newly diagnosed chronic HIV infection and varying viral loads (10 000, 30 000, 100 000, and 300 000 copies/mL) and ages (30, 40, and 50 years).
Alternative thresholds for initiating antiretroviral therapy (CD4 counts of 200, 350, and 500 cells/mm3).
Life-years and quality-adjusted life-years (QALYs).
Results of Base-Case Analysis
Although the simulation was biased against earlier treatment initiation because it used an upper-bound assumption for therapy-related toxicity, earlier treatment increased life expectancy and QALYs at age 30 years regardless of viral load (life expectancies with CD4 initiation thresholds of 500, 350, and 200 cells/mm3 were 18.2 years, 17.6 years, and 17.2 years, respectively, for a viral load of 10 000 copies/mL and 17.3 years, 15.9 years, and 14.5 years, respectively, for a viral load of 300 000 copies/mL), and increased life expectancies at age 40 years if viral loads were greater than 30 000 copies/mL (life expectancies were 12.5 years, 12.0 years, and 11.4 years, respectively, for a viral load of 300 000 copies/mL).
Results of Sensitivity Analysis
Findings favoring early treatment were generally robust.
Results favoring later treatment may not be valid. The findings may not be generalizable to women.
This simulation suggests that earlier initiation of combination antiretroviral therapy is often favored compared with current recommendations.